Once established, childhood conduct and behavior disorders are robust and have consistently negative effects on the social and academic behavior of children and adolescents. Early intervention to prevent the development of these disorders is an important alternative to intervention after problem behaviors are well established. Two factors, negative patterns of parent-child interaction associated with poor parenting skills and significant communication deficits are strongly associated with childhood conduct and behavior disorders. Therefore, developmental model of early behavior problems based on social communicative processes in parent-child interactions and a strategy for early intervention addressing the development of communication and strengthening positive parent-child social and communicative interaction are proposed. The current proposal describes an experimental investigation of a multicomponent, longitudinal intervention with families and children to prevent conduct and behavior disorders in children at high risk for these disorders. Three year old children (N=180) attending community daycares or therapeutic nurseries serving low income families, evidencing mild to moderate language delays and patterns of parent-child interaction associated with poor behavioral outcomes will be recruited. Three successive cohorts of children and families will be randomly assigned to treatment or control groups, each cohort will be followed for three years until the child enters kindergarten. Primary intervention will include parent training in communicative interactions and behavior management and direct intervention with the child to teach social communication skills in peer interactions. Secondary intervention will include classroom consultation, maintenance of parent training and child intervention as needed, family support and liaison services, and assistance during child transition to kindergarten. Positive effects on children's problem behaviors, social skills and overall development and positive effects on parent-child interaction are expected to be associated with participation in the treatment condition.